As admin says, it will work if uploaded correctly. The files are zend encoded to stop anyone stealing the script. The files must be uploaded in binary to work. If they are uploaded in ascii, it does not upload correctly, causing the error you are now getting.

Download this:
http://oldversion.com/download.php?idlo ... 21568121c0

Completely remove any old files, and use this programme to upload the script in binary. It is a radio button in the middle of the screen.

Try that.